package collection;

import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

public class MapDemo {

    public static void main(String[] args) {
        HashMap hashMap = new HashMap();
        hashMap.put("", "");
        //1,计算key的hash值，
        /*
        1.1，如果table为空，
         */

        Map<Object, Object> objectObjectMap = Collections.synchronizedMap(new HashMap<>());


        ConcurrentHashMap concurrentHashMap = new ConcurrentHashMap();
        concurrentHashMap.put("", "");

    }

}
